Summary

Insects visiting flowers to collect nectar, pollen, and other rewards often serve as important incidental agents of pollination. The efficiency of insect species as pollinators varies greatly. In this chapter, emphasis is placed on (a) the interactions between foraging insects, (b) comparison of pollinating abilities of insect sexes and castes, (c) comparisons of nectar and pollen foragers, (d) insect tongue length and its influence on flower visitation patterns, (e) characteristics of pollen grains and insect body hairs and their influence on pollen movement, and (f) pollen removal, and various other pollen losses, during insect visits. To date, most of our knowledge on insect pollination efficiency is derived from plant species growing in natural settings. Additional research is required for agricultural and horticultural crops. Some recommendations are given for future studies aimed at identifying the relative importance of different insect species as pollinators in agriculture. The importance of obtaining data within a plant species, for both insect removal and deposition of pollen, is emphasized.

Introduction

Insects are important vectors of pollen for many agricultural crops, and this chapter focuses on various characteristics that influence their efficiency as pollinators. Although some comparisons to non-insect agents of pollination are referred to herein, readers seeking information on pollen dynamics in other pollination syndromes may refer to the following: anemophily (wind pollination)–Di-Giovanni and Kevan (1991), McCartney (1994), and Niklas (1985); zoophily (mammal and bird pollination) – Fleming and Sosa (1994), and Chapter 4 of this volume.

Perhaps no other term in pollination biology has carried such ambiguity as “pollination efficiency.”